2 c All-Purpose Flour, Unbleached
2 c Light Brown Sugar -- packed
1/2 ts Ground Cinnamon
1 Stick Unsalted Butter -- cut in 6 pieces
1 lg Egg
1 ts Baking Soda
1 c Sour Cream
2 tb Milk
9 oz Semisweet Chocolate Chips, Optional
Position oven rack in the middle of the oven and preheat to 325 degrees F. Butter a 11x7x1 3/4-inch baking pan or ovenproof glass baking dish.
Put the flour, brown sugar and cinnamon in a large bowl and mix with an electric mixer on low speed for 15 seconds. Add the butter and mix till the butter pieces are the size of peas. You will still see loose flour. Mix in the egg. The mixture will still look dry. Rub any lumps out of the baking soda and gently mix the baking soda into the sour cream. Stir the sour cream mixture and the milk into the batter. Stir just until the batter is evenly moistened. Stir in the chocolate chips. The batter will be thick.
Spread the batter in the prepared baking pan. Bake about 40 minutes. To test for doneness, gently press your fingers on the top of the cake. The middle should feel slightly soft and the edges firm. A toothpick in the center should have a few crumbs clinging to it. Cool on a wire baking rack, the center of the cake will sink slightly.